JP2018204711A - Vacuum heat insulating material and refrigerator using the same - Google Patents

Abstract

A vacuum heat insulating material having low thermal conductivity and a refrigerator using the vacuum heat insulating material are provided.
A vacuum heat insulating material comprising: a glass wool core material comprising a fiber assembly; an adsorbent that adsorbs gas; and a jacket material that houses the core material. The core material is heated at atmospheric pressure. It shape | molds by performing the 2nd heat processing which heats, pressing after the 1st heat processing to perform.
[Selection] Figure 8

Description

The present invention relates to a vacuum heat insulating material and a refrigerator using the vacuum heat insulating material.

As a social effort to prevent global warming, energy conservation is being promoted in various fields in order to control CO ₂ emissions. In recent years, electric appliances, particularly household appliances related to cooling and heating, mainly use vacuum heat insulating materials to enhance heat insulating performance from the viewpoint of reducing power consumption. In addition, in order to reduce energy consumption from various raw materials to product manufacturing processes, energy saving is promoted by promoting recycling of raw materials and reducing fuel and electricity costs in the manufacturing process. . For this reason, a heat insulating material with higher heat insulating performance is required, and a long life in which the vacuum heat insulating material incorporated in the product maintains the performance for a long time is required. The vacuum heat insulating material is mainly composed of glass wool as a core material and a jacket material covering the glass wool. The glass wool used for the core material is made of glass fibers, and therefore has a large volume and needs to be processed to be inserted into the jacket material.

  In recent years, research and development aimed at improving the heat insulating performance of vacuum heat insulating materials has been vigorously advanced. For example, Patent Document 1 includes "a core material made of a glass fiber laminate in which glass fibers are laminated in the thickness direction, and an outer packaging material having a gas barrier property that covers the core material, and the interior of the outer packaging material is In the vacuum heat insulating material sealed under reduced pressure, the core material has a temperature at which the fiber starts to slightly deform due to its own weight, or a temperature at which the glass fiber can be deformed by a load from above and below during pressing. The glass fiber is pressed and molded at a temperature at which the cross-sectional shape of the glass fiber is not greatly changed, and the fiber is stretched by thermal deformation of the glass fiber, and a part of the glass fiber is not bonded to each other. A "vacuum heat insulating material that is intertwined between fibers and maintains the shape" is disclosed.

Japanese Patent No. 3580315

  In the invention described in Patent Document 1, since the core material is pressurized while raising the temperature from room temperature at a stretch, the thermal expansion coefficient at the part where the glass fibers are in contact with each other is different from the thermal expansion coefficient at the part where the glass fiber is not in contact. Due to the difference in thermal expansion coefficient, a large stress is applied to the contacted portion. When such a large stress is applied, a crack is generated in the glass fiber, and the glass fiber is likely to be damaged particularly when bending is performed. When the glass fiber is broken, the glass fiber is shortened and the heat conduction between the fibers is increased, so that the thermal conductivity as the vacuum heat insulating material is increased.

  This invention is made | formed in view of said subject, and it aims at providing the refrigerator which used the vacuum heat insulating material with low heat conductivity, and this vacuum heat insulating material.

To achieve the above object, the present invention provides a vacuum heat insulating material comprising: a glass wool core material comprising a fiber assembly; an adsorbent that adsorbs a gas; and a jacket material that houses the core material. The material was molded by performing a second heat treatment in which the material was heated while being pressurized after the first heat treatment in which the material was heated at atmospheric pressure.

According to the present invention, it is possible to provide a vacuum heat insulating material having a low thermal conductivity and a refrigerator using the vacuum heat insulating material.

It is a front view of the refrigerator in the Example and comparative example of this invention. It is a longitudinal cross-sectional view (AA sectional drawing of FIG. 1) of the refrigerator which shows the Example of this invention. It is a schematic sectional drawing of the vacuum heat insulating material which shows the Example of this invention. It is a fiber enlarged view of the core material which shows the Example of this invention. It is a fiber enlarged view of the core material which shows the comparative example of this invention. It is a figure which shows the state which performed the bending process on the vacuum heat insulating material shown in the Example of this invention. It is a figure which shows the relationship between heating temperature and moisture desorption. It is a figure which shows the performance of the vacuum heat insulating material obtained by the Example and comparative example of this invention.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a front view of a refrigerator showing the present embodiment, and FIG. 2 is a cross-sectional view taken along the line AA of FIG.
The refrigerator 1 provided with this embodiment shown in FIG. 1 has the refrigerator compartment 2, the ice storage compartment 3 (and switching room), the freezer compartment 4, and the vegetable compartment 5 from the top, as shown in FIG. The code | symbol of FIG. 1 is a door which obstruct | occludes the front-surface opening part of each said chamber, All are drawer-type except the refrigerator compartment doors 6a and 6b and the refrigerator compartment doors 6a and 6b which rotate centering on hinges 10 grade | etc., From the top. The ice storage room door 7a, the upper freezer compartment door 7b, the lower freezer compartment door 8, and the vegetable compartment door 9 are arranged. When these drawer-type doors 6 to 9 are pulled out, the containers constituting each chamber are pulled out together with the doors. Each door 6-9 is provided with packing 11 for sealing with the refrigerator main body 1, and is attached to the indoor side outer periphery of each door 6-9.

  Moreover, the partition heat insulation wall 12 is arrange | positioned in order to carry out the partition heat insulation between the refrigerator compartment 2, the ice-making room 3a, and the upper stage freezer compartment 3b. The partition heat insulating wall 12 is a heat insulating wall having a thickness of about 30 to 50 mm, and is made of a single material or a combination of a plurality of heat insulating materials such as styrofoam, foam heat insulating material (hard urethane foam), vacuum heat insulating material and the like. . Since the temperature zone is the same between the ice making chamber 3a and the upper freezing chamber 3b and the lower freezing chamber 4, a partition member 13 having a packing 11 receiving surface is provided instead of a partition heat insulating wall for partition heat insulation. A partition heat insulation wall 14 is provided between the lower freezer compartment 4 and the vegetable compartment 5 to insulate the partition. Like the partition heat insulation wall 12, it is a heat insulation wall of about 30 to 50 mm, and this is also a styrofoam or foam heat insulation. Made of material (rigid urethane foam), vacuum insulation, etc. Basically, partition heat insulation walls are installed in partitions of rooms with different storage temperature zones such as refrigeration and freezing. In the box 20, storage compartments for the refrigerator compartment 2, the ice making compartment 3a and the upper freezer compartment 3b, the lower freezer compartment 4, and the vegetable compartment 5 are formed from above, respectively. The invention is not particularly limited to this. The refrigerator doors 6a and 6b, the ice making door 7a, the upper freezer compartment door 7b, the lower freezer compartment door 8 and the vegetable compartment door 9 are also particularly limited in terms of opening and closing by rotation, opening and closing by drawer, and the number of divided doors. is not.

The box 20 includes an outer box 21 and an inner box 22, and a heat insulating part is provided in a space formed by the outer box 21 and the inner box 22 to insulate each storage chamber in the box 20 from the outside. Yes. A vacuum heat insulating material 50 is disposed in a space between the outer box 21 and the inner box 22, and a space other than the vacuum heat insulating material 50 is filled with a foam heat insulating material 23 such as rigid urethane foam. Although the vacuum heat insulating material 50 is demonstrated in FIG. 3, it is fixedly supported by the fixing member 70, the supporting member 80, etc. which are mentioned later.
A refrigerator 28 is provided on the back side of the freezer compartments 3a and 4 in order to cool the refrigerator compartment 2, the freezer compartments 3a and 4 and the vegetable compartment 5 to a predetermined temperature. The refrigeration cycle is configured by connecting the cooler 28, the compressor 30, the condenser 30a, and a capillary tube (not shown). Above the cooler 28, a blower 27 that circulates the cool air cooled by the cooler 28 in the refrigerator and maintains a predetermined low temperature is disposed.

  Insulation partitions 12 and 14 are disposed as the heat insulating materials for partitioning the refrigerator compartment 2, ice making chamber 3a, upper freezer compartment 3b, freezer compartment 4 and vegetable compartment 5, respectively. It is configured. The heat insulating partitions 12 and 14 may be filled with a foam heat insulating material 23 such as rigid urethane foam, and are not particularly limited to the foamed polystyrene 33 and the vacuum heat insulating material 50c.

  In addition, a concave portion 40 for accommodating an electrical component 41 such as a substrate for controlling the operation of the refrigerator 1 or a power supply substrate is formed in the rear portion of the top surface of the box 20, and a cover 42 that covers the electrical component 41. Is provided. The height of the cover 42 is arranged so as to be substantially the same height as the top surface of the outer box 21 in consideration of appearance design and securing the internal volume. Although it does not specifically limit, when the height of the cover 42 protrudes from the top | upper surface of an outer box, it is desirable to set it in the range within 10 mm. Along with this, the recess 40 is disposed in a state where only the space for housing the electrical component 41 is recessed on the heat insulating material 23 side, so that the internal volume is inevitably sacrificed in order to ensure the heat insulating thickness. If the internal volume is increased, the thickness of the heat insulating material 23 between the recess 40 and the inner box 22 will be reduced. For this reason, the vacuum heat insulating material 50a is arrange | positioned in the heat insulating material 23 of the recessed part 40, and the heat insulation performance is ensured and strengthened. In the present embodiment, the vacuum heat insulating material 50a is a single vacuum heat insulating material 50a formed in a substantially Z shape so as to straddle the case 45a and the electrical component 41 of the interior lamp 45 described above. The cover 42 is made of a steel plate in consideration of a fire from the outside or a case where it is ignited for some reason. In addition, since the compressor 30 and the condenser 31 arranged at the lower back of the box 20 are components that generate a large amount of heat, in order to prevent heat from entering the inside of the box, a vacuum insulation is provided on the projection surface toward the inner box 22 side. The material 50d is arranged.

  Here, the configuration of the vacuum heat insulating material 50 will be described with reference to FIG. The vacuum heat insulating material 50 is composed of a core material 51 and a jacket material 53 having a gas barrier layer covering the core material 51. The jacket material 53 is disposed on both surfaces of the vacuum heat insulating material 50, and is configured in a bag shape in which portions of a certain width are bonded together by thermal welding from the ridge line of the laminate film having the same size. The laminate structure of the jacket material 53 is not particularly limited as long as it has gas barrier properties and can be thermally welded. In the present embodiment, the surface protective layer, the gas barrier layer 1, the gas barrier layer 2, the heat It is a laminate film composed of four layers of welding layers, the surface layer is a resin film serving as a protective material, the gas barrier layer 1 is provided with a metal vapor deposition layer on the resin film, and the gas barrier layer 2 is a resin film having a high oxygen barrier property. A metal vapor deposition layer is provided, and the gas barrier layer 1 and the gas barrier layer 2 are bonded so that the metal vapor deposition layers face each other. For the heat-welded layer, a film having low hygroscopicity was used as in the surface layer.

  Specifically, the surface layer is a biaxially stretched film of polypropylene, polyamide, polyethylene terephthalate, the gas barrier layer 1 is a biaxially stretched polyethylene terephthalate film with aluminum vapor deposition, and the gas barrier layer 2 is biaxially stretched with aluminum vapor deposition. An ethylene vinyl alcohol copolymer resin film, a biaxially stretched polyvinyl alcohol resin film with aluminum vapor deposition, or an aluminum foil was used, and the heat-welded layer was a film of unstretched polyethylene, polypropylene, or the like. The layer structure and material of the four-layer laminate film are not particularly limited to these.

  For example, as a gas barrier layer 1 or 2, a metal foil or a resin film provided with a gas barrier film made of an inorganic layer compound, a resin gas barrier coating material such as polyacrylic acid, DLC (diamond-like carbon), or the like, or heat-sealed For example, a polybutylene terephthalate film having a high oxygen barrier property may be used for the layer. The surface layer is a protective material for the gas barrier layer 1, but in order to improve the vacuum exhaust efficiency in the manufacturing process of the vacuum heat insulating material, it is preferable to dispose a resin having a low hygroscopic property. Further, since the resin-based film other than the metal foil normally used for the gas barrier layer 2 deteriorates the gas barrier property by absorbing moisture, the gas barrier property can be obtained by arranging a resin having a low hygroscopic property for the heat-welded layer. This suppresses the moisture absorption of the entire laminate film. As a result, even in the vacuum evacuation process of the vacuum heat insulating material 50 described above, the amount of moisture brought into the jacket material 53 can be reduced, so that the vacuum evacuation efficiency is greatly improved, leading to higher performance of heat insulation performance. . In addition, the lamination (bonding) of each film is generally performed by a dry lamination method through a two-component curable urethane adhesive, but the type of adhesive and the bonding method are particularly limited to this. It is not necessary to use any other method such as a wet laminating method or a thermal laminating method.

Example 1
Example 1 will be described with reference to FIGS.
FIG. 3 is a cross-sectional view of the vacuum heat insulating material 50 provided in the refrigerator 1 according to the embodiment of the present invention. The structure of the vacuum heat insulating material 50 is an adsorbent (disposed in the intermediate layer of the core material but not shown) disposed between the glass wool fiber layer of the fiber aggregate forming the core material 51 and the core material 51. It consists of the structure accommodated in the jacket material 52 which wraps. A vacuum heat insulating material 50 can be obtained by heat-sealing the outer covering material 52 in a state where the core material 51 is evacuated by a vacuum packaging machine. The core material 51 can be heated and pressed after heating to obtain a thermoformed sheet-like core material 51.

  In addition, the aggregate | assembly of an inorganic fiber means the raw cotton integrally formed by the innumerable innumerable inorganic fiber manufactured by arbitrary manufacturing methods. The shape of the raw cotton is preferably a sheet having a predetermined thickness, for example, but is not limited thereto. As the aggregate of inorganic fibers, only one raw cotton or a plurality of raw cottons may be used for the convenience of the production method. That is, when it is a sheet-like raw cotton as described above, it may be a single layer or a plurality of layers. For example, inorganic fibers having an average fiber diameter of 2 to 6 μm can be suitably used, but those outside this range can also be used without any problem. Such inorganic fibers can be obtained, for example, by a centrifugal method.

  Next, a process for obtaining the sheet-like core material 51 will be described. In this embodiment, the first heat treatment heated at atmospheric pressure is performed at 400 ° C. for 5 minutes, and then the second heat treatment is performed while applying pressure for 10 minutes, so that the sheet-like core material having a small bulk is obtained. 51 can be molded. In addition, the temperature in a present Example means the surface (maximum) temperature of the core material 51. FIG.

  First, in the first heat treatment, when the temperature of the core material 51 is increased from room temperature, the glass fiber 60 is thermally expanded. However, under the condition where the pressure is maintained at atmospheric pressure (14 to 21 kg / m 3), the glass fiber 60 is heated. A portion where the fibers 60 are in contact with each other and a portion where the fibers 60 are not in contact with each other have a small difference in coefficient of thermal expansion during heating, so that a local high stress is not generated. That is, the first heat treatment without pressurization allows the glass fiber 60 to be thermally expanded without causing local high stress. Therefore, even if it performs the 2nd heat processing pressurized after that, since there is little new thermal expansion, the stress by pressurization is also suppressed and the crack generation of the glass fiber 60 can be prevented. As a result, if the core material 51 formed in this embodiment is used as the vacuum heat insulating material 50, it is difficult to break even if subjected to bending or unevenness, heat conduction due to shortening of the glass fiber 60 can be suppressed, and heat insulating performance can be achieved. It becomes possible to improve. In addition, when a crack occurs in the glass fiber 60, when vacuuming, moisture attached to the crack gradually volatilizes, the degree of vacuum is hardly increased, and the thermal conductivity as the vacuum heat insulating material 50 is likely to increase. However, according to this embodiment, since the generation of cracks can be prevented, the thermal conductivity is also kept good.

In the present embodiment, the first heat treatment is 400 ° C. × 5 minutes, but it is preferable that the temperature is 150 ° C. or more and not more than the strain point of the glass fiber 60 for 5 minutes or more. Incidentally, glass wool used in this embodiment, a B ₂ O ₃ contains about 5 wt%, but the strain point is about 500 ° C., in the case of using a high concentration of B ₂ O ₃ glass wool, the strain point Will be higher than this.

  First, the reason why the temperature is set to 150 ° C. or higher will be described. When moisture is contained in the glass fiber 60, the expansion rate of the glass fiber 60 is different and cracks are likely to occur in the fiber. Here, the moisture adhering to the surface of the glass fiber 60 can generally be evaporated at 100 ° C. or more, but the moisture associated with the OH group on the surface of the glass fiber 60 is set to a temperature higher than 100 ° C. Otherwise it is difficult to remove. However, when heated at 150 ° C. or higher as in this embodiment, even if the OH group and the H 2 O group are combined, the moisture in the glass fiber 60 is almost removed as shown in FIG. In FIG. 7, the water | moisture-content peak when the temperature rising desorption test of the glass fiber 60 is shown is shown. Moisture desorbed from the glass fiber 60 by gradually heating the glass fiber 60 is represented by an ionic current, and the heating temperature is 150 ° C. as shown by the peaks at which the water desorbs at 115 ° C. and 150 ° C. It can be said that the above is effective.

  Next, the reason for setting the heating temperature below the strain point is that when the glass fiber 60 exceeds the strain point, the portion where the fiber and the fiber are in contact with each other is fused and bonded even under normal pressure, and the vacuum heat insulating material 50 This is because the thermal conductivity increases. In the first heat treatment, unlike the second heat treatment described later, since no pressurization is performed, the heat treatment may be performed at a higher temperature than the second heat treatment, and a temperature slightly exceeding the strain point is allowed. Is done.

  In this embodiment, the second heat treatment is performed at 400 ° C. for 10 minutes, but is not limited to this, and the temperature is not lower than 300 ° C. and not higher than the strain point of the glass fiber 60, more preferably 400 ° C. or higher and 500 ° C. It is preferable to be 10 minutes or more at the following temperature. Note that the second heat treatment time is longer than the first heat treatment time.

  Here, regarding the pressure in the second heat treatment, it is preferable that the density of the core material 51 is in a range of 115 kg / m 3 or more and 460 kg / m 3 or less. In the present embodiment, glass fiber 60 having a density of 17.5 kg / m3 is pressurized to 230 kg / m3 in an atmospheric pressure state.

  The core material 51 obtained in this example has a thickness after heating and pressurization of 50 mm, a density of 84 kg / m 3 and a low bulk and a low restoration rate, so that the vacuum heat insulating material 50 with high dimensional accuracy can be obtained. And since the crack of the glass fiber 60 can be suppressed, the intensity | strength of the vacuum heat insulating material 50 improves and handling property also improves. The thermal conductivity was as good as 2.0 mW / m · K.

  Even if the vacuum heat insulating material 50 obtained by the present Example is bent, it is hard to break a fiber with the pressure applied at the time of bending. Thereby, even if it provides the bending part 70 and an unevenness | corrugation like FIG. 6 after setting it as the vacuum heat insulating material 50, it can be set as the three-dimensional-shaped vacuum heat insulating material 50 which suppressed the heat insulation performance fall.

(Example 2)
In Example 2, the first heat treatment is performed at 400 ° C. for 5 minutes, and the second heat treatment is performed at 400 ° C. for 10 minutes at a core material density of 460 kg / m 3. In the present embodiment, by increasing the applied pressure from that in the first embodiment, the thickness after pressurization becomes 35 mm, and the core material 51 having a smaller thickness can be obtained. Moreover, there were few cracks which generate | occur | produced in the glass fiber 60, and the heat conductivity when it was set as the vacuum heat insulating material 50 was able to obtain a favorable value with 2.1 mW / m * K.

Example 3
In Example 3, the first heat treatment was performed at 400 ° C. for 5 minutes, and the second heat treatment was performed at 400 ° C. for 10 minutes at a core material density of 115 kg / m 3. In this example, the pressure after pressurization is made smaller than that of Example 1, so that the thickness after pressurization becomes 60 mm and the thickness after pressurization becomes slightly larger, but there are few cracks generated in the glass fiber 60 and the vacuum heat insulating material. When the thermal conductivity was 50, the best value of 1.9 mW / m · K could be obtained.

(Example 4)
In Example 4, the first heat treatment is performed at 450 ° C. for 5 minutes, and the second heat treatment is performed at 400 ° C. for 10 minutes at a core material density of 230 kg / m 3. In this example, the temperature in the first heat treatment is higher than that in Example 1, so that the thickness after pressurization becomes 45 mm, the glass fiber 60 has few cracks, and the heat when the vacuum heat insulating material 50 is obtained. The conductivity was as good as 2.0 mW / m · K.

(Example 5)
In Example 5, the first heat treatment is performed at 150 ° C. for 5 minutes, and the second heat treatment is performed at 400 ° C. for 10 minutes at a core material density of 230 kg / m 3. In this example, by lowering the temperature in the first heat treatment from that in Example 1, the thickness after pressurization becomes 65 mm, and the thickness after pressurization is slightly larger, but the cracks generated in the glass fiber 60 are The heat conductivity when the vacuum heat insulating material 50 was small was 1.9 mW / m · K, which was the best value.

(Example 6)
In Example 6, the first heat treatment is performed at 400 ° C. for 5 minutes, and the second heat treatment is performed at 500 ° C. for 10 minutes at a core material density of 230 kg / m 3. In this example, the temperature in the second heat treatment is higher than that in Example 1, so that the thickness after pressurization is 45 mm, the glass fiber 60 has few cracks, and the heat when the vacuum heat insulating material 50 is obtained. The conductivity was as good as 2.1 mW / m · K.

(Comparative Example 1)
As a comparative example, the case where the first heat treatment is not provided and the second heat treatment is immediately heated and pressurized will be described. In this case, the thickness after heating and pressurization can be reduced to 25 mm by pressurizing the glass fiber 60 to 230 kg / m3 at 500 ° C. for 10 minutes, as shown in FIG. Deformation marks 61 that are weak in strength are generated on the surface of the glass fiber 60, and the heat insulation performance when the vacuum heat insulating material 50 is used is lowered. Further, it was found that when bending was performed on such a vacuum heat insulating material 50, the fiber in the bent portion was easily broken starting from the deformation trace 61.

In Examples 1 to 6 and Comparative Example 1 described above, only glass wool having about 5% by weight of B ₂ O ₃ was used. However, even when B ₂ O ₃ is, for example, 8% by weight, strain Although the point changed to 510 ° C., the conditions suitable for the heat treatment were almost the same as those in the above-described examples. It is the figure which expanded the fiber of the core material 51 obtained in Examples 1-6.

DESCRIPTION OF SYMBOLS 1 Refrigerator, 2 Cold storage room, 3a Ice making room, 3b Upper freezing room, 4 Lower freezing room, 5 Vegetable room, 6a Refrigerating room door, 6b Refrigerating room door, 7a Ice making room door, 7b Upper freezing room door, 8 Lower freezing room Door, 9 Vegetable room door, 10 Door hinge, 11 Packing, 12, 14 Heat insulation partition, 13 Partition member, 20 Box body, 21 Outer box, 21a Top plate, 21b Rear plate, 21d Bottom plate, 21e Side, 21f Front, 22 Inner box, 23 Heat insulating material, 23a Injection direction, 23b Foaming direction, 25 Injection hole, 27 Blower, 28 Cooler, 30 Compressor, 31 Condenser, 33 Expanded polystyrene, 40 Recess, 41 Electrical component, 42 Cover, 50 Vacuum insulation material, 51 core material, 52 jacket material, 60 glass fiber, 1 modified trace, 70 bend

Claims (5)

In a vacuum heat insulating material comprising a glass wool core material composed of a fiber assembly, an adsorbent that adsorbs gas, and a jacket material that houses the core material, the core material is heated at atmospheric pressure. A vacuum heat insulating material, characterized by being formed by performing a second heat treatment that heats while applying pressure after the heat treatment. 2. The vacuum heat insulating material according to claim 1, wherein the temperature of the first heat treatment is 150 ° C. or higher, and the temperature of the second heat treatment is lower than a strain point of the core material. Wood. 2. The vacuum heat insulating material according to claim 1, wherein the temperature of the first heat treatment is higher than the temperature of the second heat treatment. 2. The vacuum heat insulating material according to claim 1, wherein the second heat treatment is performed at a pressure at which the density of the core material is in a range of 115 kg / m 3 or more and 460 kg / m 3 or less. The refrigerator using the vacuum heat insulating material according to any one of claims 1 to 4, wherein the vacuum heat insulating material has unevenness or a bent portion.

Images